Ok, I recently reinstalled my computer with ubuntu. As it has a quadro fx 770M, I have no choice than to install the drivers myself.
I used the NVIDIA-Linux-x86-177.80-pkg1.run package, which I used in the past, and worked fine back then.
However, when I tried to install it this time, it returned me an error, stating that the kernel source files were not found. I checked everything, they are installed fine, and are located in /lib/modules/2.6.28-15-generic/build, which is a link to the /usr/src/linux-headers-2.6.28-15-generic
These files do exist, so I see no problem there.
I tried both:
sudo sh NVIDIA-Linux-x86-177.80-pkg1.run --kernel-source-path /lib/modules/2.6.28-15-generic/build
and sudo sh NVIDIA-Linux-x86-177.80-pkg1.run --kernel-source-path /usr/src/linux-headers-2.6.28-15-generic

Both these gave me the same error as before.
I have really no clue what is wrong. (It is probably some stupid mistake I'm making, but I'm quite a newbie )
I searched on google, but most of the sites I found didn't provide a working solution.